1. Field of the Invention
The present invention relates to a process for treating spirulina. The distinctive odor and taste of spirulina are minimized in treated spirulina obtained by the inventive process, making the treated spirulina highly suitable for use in products such as beverages and foods.
2. Description of Related Art
Spirulina is a food product which is rich both in nutrients characteristic of green and yellow vegetables and nutrients inherent to itself, and which enables nutrients that tend to be underrepresented in a normal diet to be easily ingested. Spirulina is generally supplied in the form of a dry powder (bulk spirulina powder). Bulk spirulina powder is typically manufactured by harvesting wet algae which has been industrially grown and produced on a large scale in an artificial outdoor pond designed for that purpose, then concentrating, washing and drying the harvested algae as needed. However, because spirulina powder produced by such a method has a characteristic odor and taste, within the food industry, it is used only in a very limited number of products, primarily health foods and specialty feeds for animals.
Methods for reducing the characteristic odor and taste of spirulina include the production process described in JP-A 7-289201, which involves adding a tea leaf extract to a cultured spirulina suspension, then drying the spirulina to a powder. However, the spirulina powder obtained by this prior-art production process continues to retain the odor and taste characteristic of spirulina.
In the food products industry in general, to maintain proper hygiene, there exists a desire to further reducing the number of undesirable bacteria such as Escherichia coli in food. For example, JP-A 63-157963 discloses a method for lowering the level of foreign bacteria in food that involves the high-temperature sterilization of an aqueous suspension composed primarily of chlorella prior to cultivating the chlorella. This prior-art publication describes an example in which chlorella, nonfat dried milk and lecithin were dispersed in distilled water, and the dispersion was passed through a high-temperature sterilizer and sterilized at about 130° C. A bacterial culture was then added and fermentation was carried out to a predetermined acidity, following which the fermented material was cooled to a temperature at which fermentation ceases, giving a food product. Although the level of foreign bacteria in the food product obtained by such a process is reduced, because the process includes treatment at a high temperature, desirable active ingredients within the food are lost.
Hence, spirulina suspensions and powders thereof which have little of the odor and taste characteristic of spirulina, contain few foreign bacteria, and retain without loss active ingredients that are desirable in food products have not hitherto been achieved.